Ediacara Hills, Flinders Ranges

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Low hills in the northern Flinders Ranges of South Australia where, in 1946, the government geologist Reg Sprigg noticed impressions of soft-bodied organisms on the undersides of sandstone slabs at an abandoned lead mine. He published them in 1947 as early Cambrian jellyfish; they are in fact older than the Cambrian, and they gave their name to the Ediacaran Period and to a whole global biota. The Ediacaran organisms are frondose, quilted, disc-like and bilaterally arranged forms preserved as casts and moulds rather than as bodies, many of them centimetres to tens of centimetres across, and a large proportion cannot be confidently assigned to any living group. Some almost certainly are animals — biomarker work on Dickinsonia recovered cholesteroids, which are characteristic of animals — while others may represent lineages that left no descendants. The type area is one of the very few places where an entire ecosystem is preserved in situ on bedding planes; Nilpena, on the adjacent plain, has had dozens of fossil bedding surfaces excavated and laid out in place, and was given national park status by South Australia in the 2020s.